A conventional weight lifting exerciser “A” is shown in FIG. 1 and includes a main frame with two guide rods 5 and weights 10 are movably mounted to the two rods 5. A cable system 20 including at least one operation cable 21 is connected to the weights 10 and reeves through several pulleys 6 and is connected to an end rod 22 as shown in FIG. 2. The end rod 22 is connected to a pulling handlebar 30 as disclosed in FIG. 1. A cable positioning assembly “B” as disclosed in FIG. 2 and includes a anti-impact ball 23 and the cable 21 extends through a passage 231 defined through the ball 23 and is connected to the end rod 22. A seal 24 is mounted to a sheath on the cable 21 and seals the opening in the first end of the passage 23. A washer 25 is mounted to the sheath and clamped between the end rod 22 and the ball 23 so as to seal the opening in the second end of the passage 23. Nevertheless, during operating the exerciser “A”, the anti-impact ball 23 in suffered frequent impact with the pulley when the cable 21 is pulled to lower the weights 10. It is experienced that the seal 24 is often disengaged from the ball 23 as shown in FIG., 2-1, and/or the ball 23 is shifted on the sheath of the cable 21 and the seal 24 is forced into the passage 231 as shown in FIG. 3. Both of the situations makes the anti-impact ball 23 become useless.
The present invention intends to provide a cable positioning assembly including an olive-shaped anti-impact member with a tube secured in the anti-impact member and the cable is secured in the tube. The combination of the anti-impact member and the tube is so strong that the anti-impact member is not moved during the operation of the exerciser.